15901_en.doc

SECTION 15901

SPACE TEMPERATURE CONTROL SYSTEM

PART 1 - GENERAL

1.1

APPLICABLE PUBLICATIONS

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

Italian Electrotechnical Committee (CEI) Publications

Publication 20-15

Italian Superior Institute for Accident Prevention and Safety at Work (ISPESL)

D.P.R. 27 April 1955 No. 547

1.2

RELATED REQUIREMENTS

The provisions of Section 15050, “Basic Mechanical Materials and Methods”, apply to this section.

1.2.1 Description of Work

The work includes providing new automatic space temperature control (ATC) systems including associated equipment and appurtenances. Provide each system complete and ready for operation. Provide control systems to maintain the conditions indicated, to perform the functions indicated, and to operate in the sequence specified. Provide control system of the electric type. Installation shall be made by or under the direct supervision of competent technicians regularly employed in the installation and calibration of automatic temperature controls (ATC). Control equipment, valves, panels, and dampers shall bear the manufacturer's nameplate. Where the distance from the sensing element to a panel exceeds the manufacturer's recommended capillary length, provide a remote transmitter between the sensing element, and the operating and adjusting mechanism at the panel.

1.2.2 Submittals

1.2.2.1 Manufacturer's Data

a.

Valves, dampers, and valve and damper operators.

b.

Controllers, including complete wiring and connections diagrams.

c.

Temperature sensors, including complete wiring and connection diagrams.

d.

Temperature and pressure indicators.

e.

Switches, relays, lights, transducers, including complete wiring and connection diagrams.

f.

Timing controls, including complete wiring and connection diagrams.

g.

Fire detection devices.

h.

Control panels.

i.

Control Acceptance Test Plan.

1.2.2.2 Shop Drawings

The shop drawings shall include the following elements:

a.

Control Schematic: Integrate with flow diagrams, show all HVAC equipment and point-to-point electrical wiring diagram including points of connection, terminals used for field connections, set points, throttling ranges, actions, spans, proportional bands, and any other adjustment. All terminals shall be numbered and cross-referenced to the ladder diagram and control panel detail. All components shall be identified by an Alpha-Numeric Designator (i.e., Cl or SQ3) and cross-referenced to the description of components and the control sequence. Show coordination with equipment having packaged controls.

b.

Ladder Diagrams: Including equipment interlocks and cross-referenced with numbered terminal points.

c.

Control Sequence: A verbal statement of the sequence of operation referring to components by their Alpha-Numeric Designator. Each system shall be broken down into subsystems such as fan sequence, heating coil sequence, etc.

d.

Description of Components: A generic description of each component and referred to by an Alpha-Numeric Designator.

e.

Control Panel Details: A layout of all control components and numbered terminal blocks. Scaled drawings indicating each control and monitoring panel. Each switch, light, gage, etc., shall be shown and include appropriate labels.

f.

Legend and Schedules: The legend shall define all symbols and the schedules shall clarify the operation of the systems.

1.2.2.3 Certificates of Compliance

a.

Valves.

1.2.2.4 Certified Data

Operator power characteristics.

1.2.2.5 Operation and Maintenance Manuals:

Space temperature control system

Submit Operation and Maintenance Data. The package shall include floor plans with device locations indicated.

1.2.2.6 Space Temperature Control System

Include items of equipment listed under paragraph entitled "Manufacturer's Catalog Data". Manual shall contain full hardware support documentation, which shall include but not be limited to the following:

General description and specifications

b. Installation and initial checkout procedures c.

Detailed electrical and logical description d.

Troubleshooting procedures, diagrams, and guidelines e.

Alignment and calibration procedures for components f.

Preventive maintenance requirements and a maintenance checklist g.

Detailed schematics and assembly drawings h.

Spare parts list data, including required tool kits and suggested method of repairs such as field repair, factory repair, or item replacement i.

Signal identification and timing diagrams j.

Complete as-built control drawings, schedules, and sequence of operation k.

Controller configuration and parameter setting procedures l.

Step-by-step procedures required for each HVAC control systems startup, operation, shutdown, recovery, and fault diagnosis m.

Manufacturer supplied operator manuals for equipment n.

Qualified service organization list

1.2.2.7 Posted Operating Instructions

Mount reduced copies of the following under glass in frames in the mechanical rooms where items are located (or near where items are located). For units mounted outside, mount operating instructions on inside of control panel door.

Control schematics showing air handling units, boilers, chillers, make-up air units, exhaust fans, unit heaters, and fan coil unit controls along with control sequences.

PART 2 - PRODUCTS

2.1 SYSTEM COMPONENTS

Sensors, industrial or commercial grade, shall be compatible with the automatic temperature control (ATC) equipment provided and shall have accuracies as stated herein. Instrument characteristics such as hysteresis, relaxation time, span, including maximum and minimum limits shall be coordinated for all application of sensors and controls, so that the control system shall operate smoothly and accurately throughout the design range.

2.2

CONTROLLERS

Provide electric type controllers and match to the devices being controlled. Controllers shall have adjustable setpoints and adjustable proportional bank for analog (proportional) control or adjustable differential for binary (two-position) control. Controllers shall have single or dual input ports as indicated or required for the sequence specified with field selectable direct or reverse action for primary, or primary and secondary inputs. Dual input controllers shall have adjustable secondary input authority. Controllers shall have integral gauge or test connections for testing or indication of all input and output signals. Gauges or meters at the output port shall indicate valve and/or damper positions.

2.2.1 Single-Loop Controllers

2.2.1.1 Controller Features

Controller shall be a microprocessor-based, single-loop device that does not require Contractor-generated software. Controller shall conform to FCC Part 15. Controller panel cutout shall be approximately 90 mm by 90 mm. Controller shall have field selectable range for process variables, a remote setpoint analog input and analog output with adjustable high and low end limits, and proportional control manual reset adjustment. Analog output shall result from PID control. Analog output shall be configurable as direct acting and reverse acting. Controller shall have keyboard, display, auto/manual selection for control of analog output, and remote setpoint adjustment/local setpoint adjustment selection. Controller shall have adjustable high-end and low-end limits, ratio, and bias adjustments on remote setpoint input; operator initiated self-tune/manual-tune selection, anti-reset, anti-reset wind-up feature, and two configurable independent SPDT with adjustable system contact closure outputs. Controller shall be configurable to power-up in manual with local setpoint control, in automatic with local setpoint control, and in automatic with remote setpoint control. Contact closures shall be activated by a process variable and by a process variable deviation from setpoint as configured. The range of hysteresis adjustment shall not be smaller than 1 percent to 5 percent of process variable input span. Controller shall power the analog output loop to 20 mA where connected to a load of 600 ohms. Controller shall have 5-year battery backup or shall have nonvolatile memory to store operating parameters.

2.2.1.2 Controller Parameter Input and Display

Controller parameters shall be entered and displayed directly in the correct engineering units, through a series of keystrokes on a front panel display with a 3-1/2-digit, seven-segment display, with decimal point and polarity indication. Use of the display shall allow manual interrogation of setpoint, mode constants, and values of process variables and outputs.

2.2.1.3 Controller Electrical Requirements

Controller shall be powered by 220 V. Controller shall provide electrical noise isolation, not less than 100 dB at 50 Hz common mode rejection ratio, and not less than 60 dB at 50 Hz normal mode rejection ratio between ac power line and process variable input, remote setpoint input, and output signals.

2.2.1.4 Controller Accuracy

Controller shall have an accuracy of plus or minus 0.30 percent of input span, plus or minus one digit.

2.2.1.5 Controller Self Tuning

Controller self-tuning operation shall apply proportional, integral, and derivative modes of control; mode constants shall be modified as required. Self tuning shall only operate when selected from the front panel.

2.2.1.6 Controller Manual Tuning

Controller manual tuning operation shall provide proportional, integral, and derivative control modes, or any combination thereof, by means of individual mode constant adjustments. Adjustments shall be set for the appropriate value if a particular control mode action is desired, or to zero for the particular mode not desired. The proportional mode constant shall be adjustable from 0 to 200 percent of input signal range; the integral mode constant shall be adjustable from 0 to 20 repetitions per minute; and the derivative mode constant shall be adjustable from 0 to 5 minutes.

2.3 TEMPERATURE SENSORS

Provide analog or binary type, as specified or indicated. Analog temperature sensors shall provide an output signal that varies linearly and continuously with the sensed temperature, within a specified range, and shall be thermistor, or resistance type. Binary temperature sensors shall provide an output signal that is either ON or OFF depending upon whether the sensed temperature is above or below the temperature setpoint and shall be electric type. All sensors of a particular category shall be of the same type and manufacturer. Temperature sensors shall be suitable for one or more of the following mounting styles: room (space) type, insertion (air duct) type, or immersion (liquid) type. Provide temperature sensors with the following characteristics:

Insertion or Immersion Type: Stem or tip sensitive type only, unless otherwise indicated.

b.

Sensing Elements: Hermetically sealed, except for bi-metal type for room thermostats.

c.

Stem, Tip, or Extended Element Construction: Type 304 stainless steel or copper.

d.

External Trim Material: Completely corrosion resistant to media in which it is inserted or immersed, with all parts assembled into a watertight (except room type), vibration-proof, heat resistant assembly.

e.

Thermometer Wells: Of bronze materials; thermal transmission material shall be compatible with the sensor.

f.

Averaging elements shall be minimum, 2.4 m long in ducts up to 2.25 sq. m and minimum 5 m for 2.2 sq. m and larger.

Room thermostats shall have external adjustments with internal locking stops for minimum and maximum settings. The visible scale shall be in degrees Centigrade. Unless otherwise indicated, room thermostats shall have a minimum cooling setting of 22.2oC and a maximum heating setting of 22oC. Covers for wall-mounted thermostats shall have polished or brushed aluminum, chrome or brass, locking type. Provide thermostats for special purposes as shown on the drawings. Mounting height of room thermostats shall be 1.2 meters from floor to top of thermostat.

2.4

ELECTRIC BINARY (TWO-POSITION) TEMPERATURE SENSORS AND CONTROLLERS

Sensors shall be bi-metal or bulb and capillary type actuating one or more switch contacts. Contacts shall be rated for the imposed load or may be pilot duty and provided with a relay. Sensors shall have adjustable setpoint spans not less than 37.8oC available throughout the range of zero to plus 121oC, adjustable differential 1.6 - 5.7oC for each contact, and adjustable differential between contact stages of 1.6 - 5.7oC and capillary tubes shall be available in lengths of 1.5 to 6m. Sensors shall not have a temperature indicator exposed to view.

2.5 SMOKE DETECTORS

Provide in Accordance with Section 13855, "Analog/Addressable Interior Fire Alarm System."

2.6 FINAL CONTROL ELEMENTS AND OPERATORS

2.6.1 Fail Safe Operation

Design and install control valves and dampers to "fail safe" in either normally open or normally closed position as required for freeze, moisture, smoke or fire protection.

2.6.2 Duct-Mounted Automatic Dampers

Provide dampers in air ducts as indicated.

2.6.2.1 Damper Assembly

A single damper section shall have blades no longer than 1.2 meters and shall be no higher than 1.8 meters. Maximum damper blade width shall be 200 millimeters. Larger sizes shall consist of a combination of sections. Dampers shall be steel or other materials where indicated. Flat blades shall be made rigid by folding the edges. Provide blades with compressible seals at points of contact. Provide channel frames of dampers with jamb seals to minimize air leakage. Dampers shall not leak in excess of 50 l/s per square meter at 100 millimeters water gage static pressure when closed. Seals shall be suitable for an operating temperature range of minus 4 degrees C to 93 degrees C. Dampers shall be rated at not less than 10 m/s air velocity. Moving parts of the operating linkage in contract with each other shall consist of dissimilar materials. Damper axles shall be 13 millimeters minimum plated steel rods supported in the damper frame by stainless steel or bronze bearings. Blades mounted vertically shall be supported by a non-ferrous dissimilar thrust bearings. Pressure drop through dampers shall not exceed 1.3 millimeters water gage at 5 m/s in the wide-open position. Frames shall not be less than 50 millimeters.

2.6.3 Operating Links: Operating links external to dampers, such as cranksarms, connecting rods, and line shafting for transmitting motion from damper actuators to dampers, shall withstand a load equal to at least twice the maximum required damper-operating force. Rod lengths shall be adjustable. Links shall be brass, bronze, zinc-coated steel, or stainless steel. Mating parts shall consist of dissimilar materials. Working parts of joints and clevises shall be brass, bronze, or stainless steel. Adjustments of cranksarms shall control the open and closed position of dampers.

2.6.4 Control Valves

2.6.4.1 Working Pressure

150 percent of system operating pressure at the valve location but not less than 860 kPa.

2.6.4.2 50 mm and Smaller

Bronze body with screwed or flared connections.

2.6.4.3 64 mm and Larger

Bronze or iron body flanged.

2.6.4.4 Trim

Brass and bronze.

2.6.4.5 Flow Characteristics

a.

Three-Way Valves: Linear with respect to percent open.

b.

Straight-Through Valves: Equal percentage for water flow control.

2.6.4.6 Maximum Pressure Drop Through Valve

Modulating Water Flow Control Valves for Coils and Apparatus: 21 kPa of water or 1/2 the pressure drop through the coil or apparatus whichever is greater.

2.6.5 Damper and Valve Operators

2.6.5.1 Electrical Valve and Damper Operators

Provide hydraulic or geared type operators. When operated at rated voltage, each operator shall be capable of delivering the torque required for continuous uniform movement of the valve or damper, and shall withstand, without damage, continuous stalling. Operators shall function properly with range of 85 to 110 percent of line voltage. Operator drive pinions and high speed gears may be made of non-metallic composition. Other gears shall be made of steel or bronze.

Shafts shall be hardened steel running in sleeve bearings of bronze, hardened steel, nylon, or ball bearings. Operators and gear trains shall be totally enclosed in dustproof metal housings with rigid conduit connections. Gear trains shall be oil immersed. Two-positioning operators shall be of the single direction spring return or reversing type. Proportioning operators shall be capable of stopping at all points in the cycle and starting in either direction from all points. Reversing and proportioning operators shall have limit switches to limit the lever in either direction unless operator is stall type. Every valve operator shall be equipped with a spring-yield device so that when in the closed position it will maintain on the valve disc a pressure equivalent to the system pressure at the valve. Electric motors shall be split capacitor type.

2.7 ELECTRICAL AND ELECTRONIC POWER SUPPLY AND WIRING

220 V or less, 50 Hz, 2-pole, 3-wire with ground. Provide wiring for control devices furnished under this section and for HVAC motor control circuits and interlock. Color code or number all wires, whether individual or in cables, for identification.

2.7.1 Transformers

Provide step-down transformers where control equipment operates at lower that the line circuit voltage. Transformers serving individual heating, ventilating, and air conditioning units shall be fed from the fan motor leads, or fed from the nearest distribution panelboard or motor control center, utilizing circuits provided for the purpose. Transformers shall have primaries wound for the voltage available and secondaries wound for the correct control circuit voltage. Transformers shall have capacity to operate simultaneously all apparatus connected to it and shall be capable of carrying 125 percent of the load for one hour in an ambient air temperature of 38oC. Transformers shall be enclosed in a steel cabinet with conduit connections and shall have a disconnect switch on the primary side, and a fuse cut-out on the secondary side.

2.7.2 Relays

Provide open contact, timed delay, mercury tube type with dustproof enclosures.

2.7.3 Manual Transfer Switches

Provide with operating levers and index plates showing switch positions and names of apparatus controlled or other appropriate designations.

2.7.4 Wiring

Provide complete electric wiring for temperature control apparatus, including wiring to transformer primaries. Provide all interlock wiring as required to perform the sequence of operation and to remotely start/stop and monitor equipment including all wiring to all devices furnished by other trades. Where motor starters are not in motor control centers, control wiring shall be provided from auxiliary contact in each motor starter. Structures shall be provided in Section 16402, "Interior Distribution Systems." Control circuit conductors run in same conduit as power circuit conductors shall have same insulation level as power circuit conductors. Circuits operating at more than 100 V shall be in accordance with Section 16402, "Interior Distribution Systems." Circuits operating at 220 V or less shall be defined as low voltage and shall be run in rigid or flexible conduit, metallic tubing, metal raceways or wireways, armored cable, or multi-conductor cable. Provide switches and fuses for the protection and convenient operation of the system. Aluminum sheathed cable or aluminum conduit may be used but shall not be buried in concrete. Protect exposed wiring from abuse and damage in an approved manner. Wire for low voltage AC shall be insulated copper 1 mm or larger and shall conform to CEI 20-15. Shield cables carrying analog signals. Cable shall terminate in solder or screw type terminal strips. Cable shall not be tapped at intermediate points. Wires, whether individual or in cables, shall be color-coded or numbered for identification. Cables terminating in screw type terminal strips shall have pressure type connectors. Wire in physical contact with compression screw will not be acceptable.

2.8

DUCT - OR CASING MOUNTED THERMOMETERS

100 mm gas-filled, dial thermometers with stainless steel movement and 1.5 m of copper averaging capillary bulb. Provide flange duct mounting and duct mounting brackets.

2.9

EQUIPMENT CONTROL PANELS

2.9.1 Equipment Control Panel

All panels shall have alphanumeric display for status and trouble. The remote alarm panel shall have both audible alarm and (red light) visual alarm in addition to alphanumeric display. The central panel display shall be capable of scrolling through status of all equipment. Panels shall be provided as indicated to collect operating data for the air-conditioning, ventilating, refrigerating and heating systems. Panels shall incorporate control, selection alarm, and monitoring devices to supervise operation of the systems as indicated. Component parts of panels shall be cubicles or cabinets constructed of black steel not lighter than 16-gage, reinforced to provide a rigid flat plate surface. Panels shall be arranged for floor mounting, unless otherwise indicated, with adequate space, 76 cm minimum, behind for maintenance accessibility. Panel faces may be constructed of aluminum not lighter than 12-gage, or of 1.25 cm thick plywood or particleboard faced on both sides with 0.15 cm self-extinguishing type plastic and having all exposed edges covered with metal trim. Electric wiring shall consist of insulated conductors installed in raceways. Nameplates shall be provided for all equipment. Nameplates shall be plastic or metal and either attached to the panel or integral with it. Lettering shall be cut into the plate to a depth of not less than 0.04 cm, and shall show in a contrasting color, produced by filling with enamel or lacquer, or by use of a laminated material. Painting of lettering directly on the surface of the plate or panel will not be permitted.

2.9.2 Graphics

Provide in a hard back binder, flow diagrams of each system and air handling unit. Flow diagrams shall be similar to those indicated as control flow diagrams. Diagrams shall show all equipment, ductwork, piping, control devices, monitoring devices and locations for each. Flow diagrams shall be printed in a permanent manner which will not fade or deteriorate. Each diagram shall be laminated in clear plastic. Provide 3 complete sets of diagrams and binders.

2.9.3 Controls

Provisions shall be made, as required or indicated, for starting and stopping equipment, with pilot lights for each piece of motor driven equipment, precision temperature indication, run time, hour meters, selection of equipment, position indicators, light canopy, improper operating condition alarm system with audible and visual alarms and sequencing of equipment.

2.9.3.1 Pilot lights shall be of the front-removable type, and a single switch shall be provided to check simultaneously all pilot lights in the panel for burnout.

2.9.3.2 Status indication for pumps, fans and air handling units shall be sensed through respective pressure differential switches. Status indication through motor starters is not acceptable.

2.9.3.3 Temperature sensing elements for temperature control may be used as sensing elements for temperature indication, except that no sensing element shall be used for both temperature control and temperature indication where an alarm or shut-down function is required.

PART 3 - EXECUTION

3.1 INSTALLATION

Provide all necessary wiring and conduit to connect the ATC components to secure an operational ATC system.

3.1.1 Workmanship

Wiring and the installation thereof shall conform to Section 16402, "Interior Distribution Systems."

3.1.2 Identification

Label or code each field wire at each end. Permanently label or code each point of all field terminal strips to show the instrument or item served. Color-coded cable with annotated cable diagrams may be used to accomplish cable identification.

3.1.3 Temperature Sensors

Stabilize sensors to permit on-the-job installations that will require minimum field adjustments or calibrations. Temperature sensor assemblies shall be readily accessible and adaptable to each type of application in such a manner as to allow for quick, easy replacement and servicing without special tools or skills. All liquid temperature sensors shall be provided with wells. Outdoor installation shall be weatherproof construction, designed to exclude driving rain or snow, or in watertight stainless steel enclosures. Sensors shall be with brushed aluminum or brushed stainless steel enclosures where located in finished spaces.

3.1.4 Duct Sensors

Provide sensors in specific location within duct that shall allow accurate sensing of the air properties indicated or specified. Do not locate in dead air spaces or positions obstructed by such items as equipment. The location of installation shall be within the vibration and velocity limits of the sensing element. Where an extended surface element is required to properly sense the average or lowest air temperature, it shall be positioned and securely mounted within the duct in a manner approved by the sensor manufacturer. Temperature sensing elements shall be thermally isolated for brackets and supports to respond to air temperature only. Provide separate duct flange for each sensing element; securely seal ducts where elements or connections penetrate duct. Seal penetrations of duct insulation vapor barrier coating compound to provide a vapor-tight covering. Mount sensor enclosures so that they may be removed and serviced without disturbance or removal of the duct insulation or vapor barrier.

3.1.5 Pipe Sensors

Provide all sensors measuring temperatures in pressure vessels or in pipes larger than 25 mm in diameter, except as specified herein, with wells properly fabricated for the service. Wells shall be non-corrosive to the medium being measured and shall have sufficient physical strength to withstand all (including test) pressures and velocities to which they are subjected. Where piping diameters are smaller than the length of the wells, provide wells in the piping at elbows to effect proper flow across the entire area of the well; wells may either look up-stream of down-stream. Provide suitable thermal transmission material within the well to speed the response of temperature measurement. Provide wells with sealing nuts to contain the thermal transmission material and allow for easy removal. Well shall not restrict flow area to less than 70 percent of line-size-pipe normal flow area.

3.1.6 Indicators

Mount all temperature and pressure indicators where they may be read by a person standing on the floor; provide remote indicators where necessary to accomplish this.

3.2 ADJUSTMENTS

Adjust controls and equipment to maintain the conditions indicated, to perform the functions indicated, and to operate in the sequence specified.

3.3

INSTRUCTING OPERATION PERSONNEL

Upon completion of the work and at a time designated by the Contracting Officer, provide the services of a competent technician regularly employed by the manufacturer of the temperature controls for the instruction of the Government personnel in the proper operation and maintenance of each automatic space temperature control system. The period of instructions shall be for not less than three 8-hour working days.

3.4

NAMEPLATES

Provide laminated plastic nameplates for all control items listed or shown in the submittal and approved control diagrams. Each inscription shall identify its function; such as "mixed air controller," "cold deck sensor," and when applicable, its position. Laminated plastic shall be 3mm (minimum) thick Melamine plastic, black with white center core. Surface shall be a matte finish. All corners shall be square. The lettering shall be accurately aligned and engraved into the white core. Size of nameplates shall be minimum 25 x 65 mm. Lettering shall be minimum 6 mm high normal block lettering. Key nameplates to a chart and schedule for each system. Mount charts and schedules under glass, in a frame, and place where directed near each system. Furnish two copies of each chart and schedule to the Contracting Officer prior to final acceptance.

3.5

TESTING

Contractor shall submit two copies of the operation and maintenance manual and two copies of a "test plan" to the Contracting Officer not less than 14 days prior to acceptance testing. Test plan shall, as a minimum, indicate how ATC system is to be tested, what variables will be monitored during test, and what criteria for acceptance should be used. Indicate how operation of HVAC system and ATC system in all seasonal conditions shall be simulated. If the Contracting Officer witnesses any tests, such test shall be subject to his approval. If the Contracting Officer elects not to witness the tests, Contractor shall provide performance certification.

3.5.1 Field Testing

Upon completion of 120 hours of continuous HVAC and ATC systems operation and before final acceptance of the work, Contractor shall test the automatic temperature control systems in service with the heating, ventilating, and air conditioning systems to demonstrate conformance with the contract requirements. Test controls through every cycle of operation, including simulation of each season insofar as possible. Test safety controls to demonstrate performance of their required function. Contractor shall furnish instruments, connecting devices, and personnel for the tests. If any of the automatic space temperature control equipment is proved to be defective in workmanship or material, adjust, repair, or replace the system. Repeat the tests to demonstrate conformance with the contract requirements.

3.5.2

SEQUENCE OF OPERATION

Shall be as indicated on the Contract drawings.

-- End of Section --

Section 15901

Section 15901